Field of the Invention
The present invention relates to a liquid ejection head, a liquid ejection head production method and a liquid ejection head production system, and particularly, relates to a structure of a liquid ejection head having a structure in which a plurality of head modules are arrayed in a single direction.
Description of the Related Art
There is known an ink-jet printing apparatus including a line-type ink-jet head having a structure in which a plurality of nozzles are provided over a length corresponding to the total width of a medium. As the line-type ink-jet head, a structure of arraying, in the width direction of the medium, a plurality of head modules in each of which a plurality of nozzle parts are arranged in a matrix can be employed.
Japanese Patent Application Laid-Open No. 2015-047833 describes a liquid ejection head configured to joint, in a single direction, a plurality of head modules in each of which a plurality of nozzle parts to eject liquid are arrayed. The liquid ejection head described in Japanese Patent Application Laid-Open No. 2015-047833 is configured to alternately joint a first head module in which the ejection volume of the liquid at one end part of the head module with respect to the array direction of the head module is greater than the ejection volume of the liquid at the other end part and a second head module in which the ejection volume of the liquid at the other end part is greater than the ejection volume of the liquid at one end part, and thereby, the density unevenness at joint parts of the head modules is suppressed.
Here, the terms “droplet”, “ejection amount” and “recording head” described in Japanese Patent Application Laid-Open No. 2015-047833 correspond to the terms “liquid”, “ejection volume” and “liquid ejection head” in the specification, respectively.
Japanese Patent Application Laid-Open No. 2007-022092 describes an ink-jet recording apparatus that generates image data such that a line graph showing density change characteristic depicts a line having a grade when the density change characteristic of an image to be drawn by the liquid ejection head is shown as the line graph, and that performs the drawing based on the generated image data.
The ink-jet printing apparatus described in Japanese Patent Application Laid-Open No. 2007-022092 performs such a control that the density changes continuously and gradually, allowing for the inconspicuousness of the image degradation due to the density unevenness by the liquid ejection head.
Here, the terms “printing head” and “ink-jet printer” described in Japanese Patent Application Laid-Open No. 2007-022092 correspond to the terms “liquid ejection head” and “ink-jet recording apparatus” in the specification, respectively.
Japanese Patent Application Laid-Open No. 2007-160834 describes a liquid ejection head in which a plurality of head modules are arranged along the array direction of nozzles. By arranging the head modules in order of the magnitude of average ejection volume or by equalizing the first head module and the N-th head module in average ejection volume, the liquid ejection head described in Japanese Patent Application Laid-Open No. 2007-160834 reduces the density unevenness caused by the difference in ejection volume among the head modules, and achieves the improvement in image quality.
Here, the terms “recording element substrate”, “ejection amount” and “ink-jet recording head” in Japanese Patent Application Laid-Open No. 2007-160834 correspond to the terms “head module”, “ejection volume” and “liquid ejection head” in the specification, respectively.